Dubbed "Bing Basic" in an April 1 blog post, and claiming it was a special test, the prank kicks off "if you visit bing.com and enter a certain telltale query" that then results in "something a little more bland."

From Bing.com, users simply enter "Google" to see a temporary home page that looks very much like Google's noted minimalist design.

"We decided to go back to basics, to the dawn of the Internet, to reimagine Bing with more of a 1997, dial-up sensibility in mind," wrote Michael Kroll, principal UX (user experience) manager for Bing, on the blog. "We may see some uptick in our numbers based on this test, but the main goal here is just to learn more about how our world would look if we hadn't evolved."

SearchEngineLand first reported on the "Google" trigger for the Bing Basic hoax.

The revamped Bing Basic screen sports a few differences from Google's real home page, including a renaming of the latter's "I'm Feeling Lucky" button to "I'm Feeling Confused." Clicking on that button in Bing's imitation leads to Kroll's blog post.

Microsoft has retained Bing's hover-links, however, and used them to take additional shots at the competition. Hovering the mouse over one such link displays a pop-up that states, "When there's nothing else to look at ... You may take drastic measures." Clicking directs the user to a search for "watching paint dry."

Google's counter -- launched earlier in the day -- was both more elaborate and more subtle as it spoofed Microsoft's Outlook.com email service, the rebrand of Hotmail.com that debuted last July.

Called "Gmail Blue," the phony is purportedly a major refresh of Google's own email service that "Richard Pargo," supposedly a project manager, says was based on the question, "How do we completely redesign and recreate something while keeping it exactly the same?"

While some have interpreted Google's gag as a shot fired at Windows 8 -- both directly at the summer's upcoming upgrade, code named "Blue," as well as critics' take on the new OS, which makes a radical change of user interfaces (UIs) in one part, while retaining the traditional desktop in the other -- it could also be seen as a bashing of Outlook.com, which by default features a blue theme.

"I think the first thought that's going to come to the end-user's mind is, 'I can't believe I waited this long for this,'" concluded "Carl Branch," labeled as lead engineer.

Not coincidentally, today was Gmail's ninth anniversary. Google launched its invitation-only beta of the service on April 1, 2004.